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2 SOPS Bids Farewell To Miracle GPS Satellite

Bruce Carlson (center), Boeing technical advisor, and Mike O’Brine (right), Aerospace Corporation, send the final command to dispose of Global Positioning System Satellite Vehicle Number 23 at Schriever Air Force Base, Colorado, Friday, Aug. 26, 2016. Both of them were on the operations floor November 1990, when the satellite initially launched and when the solar array stopped working. They, along with the operators working, saved the satellite by tweaking its operating mode, and extended its life to 25 years. Image Credit: U.S. Air Force/2nd Lt. Darren Domingo

Older, less capable satellites, such as SVN-23, are moved into a disposal orbit at end of life to reduce risk to the GPS constellation, and to create space for more satellites. Since GPS satellites do not carry the amount of fuel required for de-orbit maneuvers, they are instead pushed to a higher orbit, roughly 1,000 kilometers above the operational GPS orbit.

“It’s a story of the men and women who’ve been doing this for a very long time, keeping these vehicles alive much longer than expected,” said Capt. Aaron Blain, 2 SOPS DOA (analysis) flight commander.

SVN-23 has a unique story, as its journey of almost 26 years came with a rough beginning – it severely malfunctioned in its initial orbit. 2 SOPS contractors Bruce Carlson and Mike O’Brine were on the operations floor when the satellite’s solar array stopped working.

“We launched it on the 26th of November, 1990. We finished early-orbit operations in the early part of December, we managed to stabilize it, and 12 hours after we did that, the A side of the solar array drive failed,” explained O’Brine.

At the time, the operators realized the design flaw in the vehicle. If they did not correct the malfunction, SVN-23 would have additional failures, which could actually endanger their ability to dispose of it.

“The crew said, ‘Hey what’s up with this?’ We looked at it and said, ‘Oh, it looks like the solar array appears to have failed to power off conditions. We’ll just power it back on and it will come back on. Oh wait, it didn’t.’ That was a fun day or two when that happened,” chuckled Carlson.

The team had to switch the solar array’s mode to the second drive motor to save the vehicle’s life.

“For the next 14 years, twice per orbit, we had to run a technique, which is called scissoring, where (during) orbit dawn and orbit dusk, we had to manually command the solar arrays back and forth, all from a ground command,” said O’Brine.

In 2005, a decision was made to allow normal operations on the B side of the solar array drive and miraculously it worked for the remaining 11 years of life on the vehicle. The extra care and diligence with SVN-23, through hundreds of operators and contractors, sustained the 25-year-old satellite’s life to the final command Friday, a bit of a marvel, since the design life of the spacecraft was only supposed to be 7.5 years.

Lt. Col. Peter Norsky, 2 SOPS commander, gave a word of encouragement to his team on the operations floor during SVN-23’s final command ceremony.

“This is just an incredible event and I’m really proud that you all have put so much into (SVN-23) and every single one of our birds. Having something last this long is truly a testimony to (our) operations. Every single day that you are all on the ops floor, you’re contributing to things like this, so thank you for what you do,” he concluded.

Air Force Space Command’s 2nd Space Operations Squadron (2SOPS), based at Schriever Air Force Base, Colorado, manages and operates the GPS constellation for both civil and military users.